Add fields for event host(s) and event speaker(s)

Is your enhancement related to a problem? Please describe.

A need for those fields were mentioned in user feedback

event host(s) as they could be different than the person publishing the event, and not listed in the "leadership" tab, sometimes people host an event as a guest host
event speaker(s), in order to list them as speaker

This would be beneficial to GatherPress either as a standalone plugin, or in the use of GatherPress on the WordPress community.

Those fields should be looking for usernames and allow to pick existing users. If several, as comma separated values, similar to choosing tags

Designs

No response

Describe alternatives you've considered

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Code of Conduct

[X] I agree to follow this project's Code of Conduct

I thought about this kind of relation a user can have with an event very intens lately and have read the related issues here probably 10 times. (#3, #445, https://github.com/GatherPress/gatherpress-wp-org-integration/issues/5)

I’d could be helpful to step back a little bit, to broaden the perspective from technical-only to technical-and-philosophical.

For the migration from the custom RSVP DB table to the comments table, we concluded that in WordPress an interaction of a human being with any data is called „comment“. We translated the human-readable „I take part in an event as attendee“ into a new comment with the comment_type of RSVP and assigned the „attending“ term to that comment.

Now let’s do the same (or similar) for speakers, organizers and maybe even sponsors.

If someone speaks, organizes or sponsors an event, it’ll be a comment on that event by the explicit user.

This makes sure:

one user can have multiple roles per event
one user can have different roles per each event
A site owner can could open a „call for speakers“ with a simple (little modified) comment form (block)
A request to speak/organize/sponsor (via the comment API internally) will be queued and can be approved automatically or manually (like comments)
GatherPress can re-use most of the built-in stuff without reinventing new wheels, like numerous comment-blocks, spam-protection, template tags and endless hooks.

While this only touched the technical implementation, the UI for such a thing could be like described by @patriciabt with a user-select for each role.

User that are selected as site-wide organizers in the GatherPress settings, could/should be automatically assigned on event creation, means they will get an comment created in their name.

This is not meant to replace the need for explicit Roles & capabilities, but could be its foundation. Someone could earn the permission to edit an event, if this exact user has made a comment (with comment_type rsvp and term organizing), which got approved. Going this way would allow GatherPress to assign all or some of the special capabilities @javiercasares described in #445, without having to use explicit WordPress roles or custom capabilities, that a site owner might need to assign to somebody in the first hand. Those caps could be assigned dynamically based on the comment, using user_has_cap .

All of this should be nicely wrapped in a sense-making API, but under the hood, it’s just comments.

GatherPress / gatherpress